On 11/2/2016 2:13 PM, Steve Willner wrote:
how does that affect the "concordance"? Cosmology has all but
completely accepted Dark Energy as real, can they take another
shock to the system where all of a sudden it isn't anymore?

The reason Dark Energy is widely accepted is because it fits all
existing data, and so far no model without Dark Energy does.

If someone does come up with a model that fits the data without Dark
Energy, that model will be evaluated on its merits: how well does it
fit the data, and how many free parameters does it have?

Well, before there was Dark Energy, there was a model that fit the data
too. That was the hot Dark Matter model, where the place of Dark Energy
was filled by neutrinos.

I might point out, though, that a cosmological constant is an
inherent part of the Friedmann equations. Its value might be zero
(as was widely assumed before the evidence came in), but there's no
reason I can see for favoring zero over any other value. Indeed
quantum mechanics suggests the cosmological constant ought to be
enormous. From that point of view, the problem is explaining why
Dark Energy is so small.

Well, that Dark Energy size vs. Vacuum Energy disconnect has been around
ever since the DE was first discovered. If the entire amount Vacuum
Energy were available as Dark Energy, then likely the universe would've
blown up milliseconds after the Big Bang, with an even Bigger Bang.

In fact, I wonder if something like that didn't actually happen? If that
entire Inflation after the Big Bang wasn't as a result of the universe
getting rid of a little extra vacuum energy?

Yousuf Khan